Block system for railways.



G. W.'NIS'TLE, E. INSKIP & B. W. BRADY.

BLOCK SYSTEM FOR RAILWAYS.

APPLICATION FILED JAN. 2, 1908.

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m uw gm a a; W. NISTLE, B. INSKIP & B. w. BRADY.

BLOCK SYSTEM FOR BAII IWAYS.

' APPLICATION FILED JAN. 2 1908. 928,273.

- Patented July 20,1909.

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ANDREW B. emu m, PMOTOAJYNOGRAPHERE. WASHINGTON,

UNITED STATES PATENT OFFICE.

GEORGE W. NISTLE, OF MUSKEGON, MICHIGAN, AND BERNARD W. BRADY AND EDWARDINSKIP, OF CHICAGO, ILLINOIS.

BLOCK SYSTEM FOR RAILWAYS.

To all whom it may concern:

Be it known that we, GEORGE W. NISTLE, residing at Muskegon, in thecounty of Mus kegon and State of Michigan, and BERNARD W. BRADY andEDWARD INSKIP, residing at Chicago, in the county of Cook and State ofIllinois, all citizens of the United States, have invented certain newand useful Improvements in Block Systems for Railway- Bridges, of whichthe following is a specification.

This invention relates to improvements in block systems for railwaybridges, and refers more particularly to improvements in a system ofthat general type in which mechanism. located along a track cooperateswith mech anism upon the train to automatically arrest the latter incase the train attempts to cross an open draw or bridge.

Among the salient objects of the invention are to provide a system whichis completely automatic in its arresting functions and of reliableconstruction and operation, thereby eliminating the personal equation tothe greatest practical extent; to provide a system whereby a trainapproaching a bridge automatically locks the latter and at the same timeouts of? the power which operates the bridge, until the train has passedover the latter whereupon the train automatically restores the system toits normal condition; to provide a system in which the opening of thebridge automatically sets the blocking mechanism in danger position andautomatically restores the system to normal cleared condition by aclosing of the bridge; to provide signaling mechanism for warning theengineer of an approaching train in case the block is in dangerposition; to provide other signaling mechanism for notifying the bridgetender that an approaching train has locked the bridge and cut off theoperating power; to provide simple and effective mechanism forcooperating with the air brake system whereby said air brake system isbrought into operation automatically in case the blocir conditions weresuch that this should be done; to provide an improved type of tracklever which cooperates with mechanism upon the train and in general toprovide an improved construction of the character referred to.

Specification of Letters Patent.

Application filed January 2, 1908.

Patented July 20, 1909.

Serial No. 408,946.

The invention consists in the matters hereinafter described and moreparticularly pointed out in the appended claims.

In the accompanying drawingsFigure 1 shows diagrammatically anembodiment of the system as applied to a swinging bridge equipped with asingle railway track. Fig. 2 is a detail side elevation of one of thetrack instruments, parts being broken away to reduce the size of thedrawing. Fig. 3 is a side elevation of the other track instrumentdiffering slightly in details of equipment. Fig. 4 is a detailedsectional view of the blocking latch mechanism, taken through lines 44of Fig. 2. Fig. 5 is a sectional view of one of the contact devicesshown in open position. Fig. 6 is a detailed sectional view of thefrictional latch mechanism taken through lines 66 of Fig. 2. Fig. 7 is aside elevation of the controller wheel and associated mechanism, partsof the wheel being broken away to reduce the size of the drawing. Fig.Sis a fragmentary detailed view of one of the contact devices upon thebridge.

In carrying the present invention into ef fect, we employ a novel typeof circuit controlling track instrument which takes the form of a leverhaving one. or more tread surfaces inclined relatively to thehorizontal. Each of these instruments is provided with contact makingdevices controlling circuit connections which lock or clear the block.Some of these instruments are also provided with blocking mechanismwhereby they are .rnechanically held against oscillation by a passingtrain. These instruments are located along the rails of the track inpos1t1on to be encountered by a controlling wheel carried in somesuitable manner by some part of the train; and this controlling wheelis, under certain conditions, raised or forced upwardly by the trackinstruments, to thereby vent the train pipe of the air brake mechanismof the train.

In the diagram A designates as a whole a draw or turn bridge mountedupon a base 1 and provided with gear mechanism designated as a whole 2which is swung into its open or closed positions through the action of adriving shaft 3 operated by an electric motor 4.

D and C designate the track instruments,

a pair of which are arranged at either end of the block.

B designates as a whole a semaphore for warning an approaching train,and E designates the signal mechanism for notifying the bridge tender.

F designates the mechanism for locking the bridge in closed position.

Describing now the several track levers, and referring to Fig. 2, theinstrument there shown is that designated C. This instrument ispivotally mounted at 16 upon a suitable base plate 15 fastened to across tie or other support upon the road bed. This lever is desirablymade from angle iron so as to be both light and strong and is bent toprovide oppositely downwardly inclined track surfaces 17*17 andconverging intermediate surfaces 18-13. his lever is so supported,relatively to the line of travel of the controller wheel which actuatesthe lever that it may be oscillated twice by the passage of a trainthereover. This lever is weighted at its rear end so that when it is notpositively held in one of its positions it will return to its normalposition, i. c. with its front end elevated. The depression of theforward end of this lever is positively controlled by a magnet M and acooperating latch mechanism. Describing th1s latch mechanism, andreferring to Fig. 4, upon the side of the lever op )osite the magnet Mis mounted a latch block 20 having a shoulder 21 with which is adaptedto cooperate a latch 22 pivoted at its lower end as indicated at 23, andcarrying an armature 24 which is acted upon by the end of the magnet. Aspring 25 interposed between the latch and the head of the magnet spooltends to press the latch away from the magnet and into engagement withthe latch block 20. The rear end of the lever is also controlled by afriction latch mechanism adapted to hold the lever yieldingly in eitherof its two positions in which it happens to be left. This friction latchmechanism comprises a magnet N arranged to act upon a pivoted latchmember 26 carrying an armature 27 and provided at its upper end with aconical or double inclined engaging end 28 which cooperates withcorrespondingly shaped recesses 29 and 30, formed in the side face ofthe lever and at suitable points corresponding to the two positions ofthe lever. This latch is normally held in engagement with the lever bymeans of an expansion spring 31 interposed between the latch and thehead of the magnet spool. Upon the rear end of this lever is mounted acontact plate 32 which cooperates with a pair of plates 33 mounted upona suitable fixed support 34 below the lever; the relative arrangement ofthese parts being shown clearly in Fig. 5.

in Fig. 3 is shown the lever designated D in the diagram. The generalconstruction and shape of this lever is, or may be, precisely the sameas that of the instrument C. It is similarly pivoted at 16 to a baseplate 15 and is weighted at its rear end as indicated at 35, so as totend to return to its normal position. This leveris employed formomentarily closing a circuit while the controller wheel is passingthereover. To this end the forward end of the lever carries a contactplate 32 which cooperates with a pair of contact plates 33 mounted upona support 34 in ex actly the same manner as the contacts carried by thelevers C.

Next describing the controller wheel and its associated mechanism, andreferring to Fig. 7, upon a suitable part of the train, as for exampleupon the ournal box of one of the axles of the tender, is mounted aframe designated as a whole 36, and which in turn carries a lever 37pivotally mounted between its ends, as indicated at 38. A pipe 39connected with and leading from the air train pipe of the train, extendsthrough a suitable block or support 40 upon the frame 36, and terminatesin a cap 41 which is normally held upon the pipe so as to close and sealthe latter by means of an-upright-lever 42 pivoted at 43 upon the frame36. This lever is held in position to retain the cap 41 by an extension44 of the lever 37; the arrangement being such that when this end of thelever 37 is depressed it releases the lever 42 and vents the train pipe.Upon the longer end of the lever 37 is pivotally mounted the controllerwheel 45 which cooperates with the several levers hereinbeforedescribed. This controller wheel is held against rising until itencounters a lever which is held positively in fixed position,

by means of a relatively stiff spring 46 mounted upon the frame 36 andbearing upon the upper side of the lever 37. When the controller wheelhas been elevated so as to release the lever 42, vent the train pipe andso apply the brakes and arrest the train, the

parts associated with the controller wheel will be restored to theirnormal positions manually by the train men.

Describing now the contact devices associated with the bridge proper, acontact plate 47 is secured to but insulated from the bridge, and isadapted to cooperate with a pair of contact plates 48 upon the bank.Upon the rotating collar 49 of the bridge is rigidly mounted a contactdevice 50 which cooperates with a contact ring 51 upon the basesupport 1. As seen in the diagram the contact ring 51 as well as thecontact device 50 are insulated from their supports. Upon the side ofthe bridge opposite the contact 50, a contact screw 52 is secured to thering 51. In order to effectually set the blocking mechanism in dangerposition in case the bridge is destroyed by fire or any other means, thecontacts 47 and 50 are connected by a fusible wire 53 which extendsacross the length of the bridge. This wire is adapted to with stand anyordinary current which may be sent through .it but will fuse in case itis exposed to great heat and thus break certain circuit connections asWIll hereinafter more clearly appear.

Describing new the bridge operating mechanism, the motor 4 is drivenfrom any suitable source of current supply (not shown) and is controlledby the bridge operator through means of a switch54. This current supplyis also automatically controlled by a switch 55 pivotally mounted at 56and carrying a contact lever 57. This lever 57 is provided with anarmature plate 58 which is so controlled by a magnet P as to close the169. This lever 69 is pivoted trolled by a solenoid switch when themagnet P is energized. The rear end of the lever 57 is weighted. asshown at 59 so that switch 55 will be opened by gravity when the magnetP is deenergized. It will thus be seen that the magnet P through theaction of this switch lever positively controls the source of current tothe motor.

The bridge locking mechanism F is con- 60 and windings 61. This solenoidis pivotally mounted at 62 by means of a lever arm 63 which carries aweighted extension 64. As seen in the diagram these parts are soarranged that when the windings 61 are energized the solenoid willwithdraw the locking mechanism from the bridge, while when the windingsare deenergized the weight extension will force the look into the bridgeby gravity.

In order to notify the bridge operator that the bridge is locked and thepower has been cut off, we provide the signaling mechanism designated asa whole E. Thismechanism comprises an electric bell 65 and a visiblesignaling disk 66 adapted to be operated by the closing of the circuitthrough a battery 67. The disk mechanism is constructed similarly to theswitch lever 55, being provided with an armature carrying lever 67 and aweight extension 68. The lever 67 being controlled by a magnet S incircuit with the battery 67 The circuit of the battery 67 is normallybroken by means of a contact carrying lever at 70 and weighted at itsrear end as indicated at 71, and is provided with an armature 72controlled by a magnet It will be seen that these parts are so arrangedthat when the magnet R is energized the lever 69 will be pulleddownwardly and the circuit of the battery 67 broken. On the other handwhen the magnet Ris deen ergized the weighted extension 71 willoscillate the rear end. of the lever 69 downwardly thus closing thecontacts on the forward end of that lever and closing the circuit whichoperates the bell 65 and the disk 66.

At the forward end of the block is situated the semaphore B weighted atits rear end as indicated at 73 and controlled by a magnet T.

The circuits of the system which utilizes the mechanisms just describedwill now be traced.

Referring to diagrammatic Fig. 1, the systern is therein shown asorganized for controlling the single track which passes over a turn ordraw bridge.

At the entrance to the block the lever D stands in open circuitposition, and the lever C is also in its normal position i. c. with itsweiglited end. down. As the train enters the block it first encountersthe lever D and as the controller wheel passes over the same, itimmediately closes a circuit which energizes a magnetN at the forward.end of the block. This circuit may be traced as follows: from line L byway of conductor 75 through branch conductor 76 through the windings ofthe forward magnet N thence by way of conductor 77 to the contacts onthe rear lever D, and thence to ground. at 78. The energizing of theforward magnet N does not at this time perform any electrical functioninasmuch as the forward lever C is in its normal position; but as willhereinafter appear this circuit is useful when a train is backing acrossthe bridge.

When the controller wheel encounters the rear lever C it will pass overthe rear end of that lever without oscillating the same inasmuch as thelever is at this time in its normal position. However as the wheelpasses over the forward end of the lever it will oscillate the latterunless the latch 22 is in locked position t. c. with its controllingmagnet M deenergized. If the bridge is closed however the magnet M willbe energized and the latch withdrawn. The circuit controlling the magnetM may be traced as follows: from line L by way of conductor 7 9 through.the windings of the rear magnet M to conductor 80 next to the forwardend of the block to the junction point 81 and common conductor 82 to thecontact ring 5]. at the base of the bridge, thence by way of contactbrush 50 to the fuse wire 53, from the fuse wire to the contacts 47 and48 and thence to ground at 83. It might be here stated that the lockinglatch of the forward lever C is at the same time withdrawn through theenergizing of the forward magnet M. The circuit which energizes thislatter magnet extends from line L and. conductor 75 and 84 through thewindings of the forward magnet M to the junction point 81, and thence byway of common conductor 82 to ground at 83 as hereinbefore described.

It will be remembered that when the eontroller wheel passed over therear lever C it elevated the rear end of the latter and broke thecontacts at the rear thereof. The lever remains in this latter positioni. c. with its rear end elevated through the action of the frictionlatch 26 inasmuch as the rear magnet N is at this time deenergized. Thecir cuit controlling the rear magnet N may be traced as follows: fromline L and conductor 79 to branch conductor 85, thence through thewindings of the rear magnet N to conduc tor 86, by way of conductor 86to the for ward end of the block to the contacts of the forward lever D,and thence by way of conductor 87 to ground. at 88. But inasmuch as thecontacts on the forward lever D are at this time broken it will be seenthat the rear magnet N will be deenergized.

The breaking of the contacts on the rear lever C deenergizes the magnetsP and R and the windings 61 of the solenoid 60. It will be rememberedthat these magnets and the windings are so arranged that thedeenergizing thereof will respectively out off the power of the motor 4,close the circuit of the operators signaling mechanism and lock thebridge. The circuit which controls the mag net P extends from line Lthrough the windings of that magnet thence by way of conductor 89 to acommon junction point 90. The circuit which controls the magnet R e):-tends from line L by way of conductor 91 through the windings of themagnet R and thence by way of common conductor 89 to the same junctionpoint 90. Similarly the circuit of the windings 61 extends from line Lconductor 92 through the windings 61 to conductor 93 and thence to thejunction point 90. From the junction point 90 the several circuits ofthese magnets and the solenoid windings may be traced to ground asfollows: from junction 90 by way of con ductor 9 1 to the contacts ofthe rear lever C (at this time open) thence by way of conductor 95 tothe contacts of the forward lever C at the front end of the block. Andfrom these contacts by way of conductor 96 to ground at 88. It will thusbe seen that the circuits which energize the magnets P and R- andv thewindings 61 are positively controlled by means of the contacts on thepair of levers C. Inasmuch as the bridge is now locked, the power outoff, and the bridge op erator notified by means of the signalingmechanism, the train may safely pass over the bridge. When the train haspassed over the bridge and reaches the forward end of the block, it willfirst encounter the forward lever C and as it passes over the latterwill twice oscillate it, thereupon returning it to its normal position.The controller wheel of the train may at this time ride over the forwardend of the lever C inasmuch as the blocking latch is at this timewithdrawn by its magnet as hereinbefore stated. As the train passes outof the block it will depress the forward end of the lever D thusmomentarily closing the circuit which controls the rear magnet N andenergize the latter. The energizing of the rear magnet N will withdrawthe latch 26 and permit the contacts of the rear lever C to return totheir normally closed position by gravity. This closes the circuitswhich control the bridge lock, power circuit and operates signalingdevice and the system is again in cleared position. It might be herenoted that the energizing of the windings 61 will center the solenoid60thus bodily withdrawing the lock F from the bridge. The action of thepower switch and lever 69 of the signaling circuit have hereinbeforebeen fully described.

The system herein shown is so arranged that a train may also safely backover the bridge. Assuming that the various mechanisms are in theirnormal cleared positions, the backing train will first encounter theforward lever D and momentarily close the contacts thereon withouthowever performing any electrical function. As the controller wheelpasses over the forward lever C it will elevate the rear end thereofthus breaking the contacts on the rear end of this lever. The breakingof these contacts takes off the ground 88 from the circuits whichcontrol the magnets P and R and the windings 61, thereby cutting off thepower circuit operating the bridge, the tenders signaling mechanism andlocking the bridge. This, of course, permits the train to safely passover the bridge. It might be here noted that the contacts of the forwardlever C will now remain broken through the action of the friction latch26 inasmuch as the magnet N is at this time deenergized, its circuitbeing broken at the contacts of the rear lever D. When the backing trainhas crossed the bridge and reaches the rear end of the block, it willtwice oscillate the rear magnet C returning it however to the positionin which it found it. As the backing train passes out of the block itwill oscillate the rear lever D thus momentarily closing the circuitthrough the contacts of this lever. This energizes the magnet N at theforward end of the block withdrawing its latch 26 and permitting theforward lever C to return to normal position thus clearing the block.

From the foregoing it will be seen. that a backing as well as anadvancing train may safely pass across the bridge and as each leaves theblock will automatically restore the system to its normal or clearedposition.

In case the bridge operator desires to open the bridge, the system is soarranged that the blocking levers will be set at either end of the blockand the semaphores will like wise each be set in danger position. Thecircuits which control the latches 22 of the blocking levers have beenhereinbefore described and need not be retraced. It will be rememberedthat they are controlled through the contacts 47 and 48 and the fusewire 53. It will thus be seen that as the bridge is opened the ground83will be taken off through the separating of the contacts 47 and 48, thusdeenergizing the magnets M and placing the blocking levers Gin dangerposition. It will be likewisenoted that in case the fuse wire bedestroyed, this circuit will of course be broken.

In order to warn the engineer of a train approaching in eitherdirection, that the bridge is open and the levers C in blocked position,we provide at either end of the block a semaphore B of well knownconstruction. Each of these semaphores is controlled by a magnet T andso arranged as to be set in danger position by the de'c'nergizing of themagnets T as hereinbefore described. The circuit which controls the roarmagnet T extends from line L to conductor 97, thence through thewindings of magnet T to conductor 98, from conductor 98 to conductor 80to the forward end of the block and thence by way of the commonconductor 82 to ground at 83. The circuit which controls the forwardmagnet T may be similarly traced to the common return conductor 82.

When the bridge returns to its closed position, it closes the circuitswhich energize the magnets M and T, and the blocking levers andsemaphores are placed in their respective normal positions.

While we have herein shown an embodiment of the invention which for sakeof clearness is shown as applied to a single track, it is obvious thatit may be changed in the various constructions of the operatingmechanisms and in the connections of the circuits without in any mannerdeparting from the spirit of our invention.

We claim as our invention:

1. In a block system for railway bridges, the combination with a bridge,and a length of track crossing said bridge, of a set of pivotallymounted train actuated contact controlling levers associated with saidtrack beyond each end of said bridge, and adapted to be oscillated bythe traverse thereover of a traversing member carried by a train,electrical contact devices controlled by the respective sets of levers,bridge mechanism for operating and for locking the bridge, circuitconnections controlling said bridge mechanism and including saidelectrical contacts, whereby the passage of said traversing member oversaid sets of levers successively placesaid bridge mechanism ininoperative and operative condition.

2. In a block system for railway bridges, the combination with a railwaybridge, of a length of track crossing said bridge, a set of pivotallymounted train actuated contact controlling levers associated with saidtrack beyond the respectiveends of said bridge,

and adapted to be oscillated by the traverse thereover of a traversingmember carried by a train, electrical contact devices controlled by saidlevers, bridge mechanism, circuit connections for controlling saidbridge mechanism and including said contact devices, whereby the passageof said traversing memher over said. sets of levers successively placesaid bridge mechanism in inoperative and operative condition.

3. In a block system for railway bridges, the combination with a railwaybridge,of a length of track crossing said bridge, a set of pivotallymounted train actuated contact controlling levers associated with saidlength of track beyond each end of said bridge and adapted to beoscillated by the traverse thereover of a traversing member carried by atrain, electrical contact devices controlled by said levers, means forlocking said bridge in closed osition, and circuit connections forcontro ing said locking member and including said. electrical contactdevices whereby the passage of a traversing member over said sets oflevers electrically controls said bridge locking mechanism.

4. In a block system for railway bridges, the combination with a bridge,of a length of track crossing said bridge, bridge locking mechanismassociated with said bridge, normally closed train actuated contactdevices arranged at either end of said length of track and beyond therespective ends of said bridge, means for holding said contact devicesyieldably in the position in which they are left by the passagethereover of a train, and circuit connections controlling said lockingmechanism and including said train-actuated contact devices.

5. In a block system for railway bridges, the combination with a bridge,of a length of track crossing said bridge, train actuated contactdevices associated with said length of track, signaling mechanismassociated with said bridge, a local battery circuit for operating saidsignaling mechanism, contact devices included in said local batterycircuit, a magnet controlling said contact devices, and circuitconnections including said magnet and said train actuated. contactdevices whereby the latter electrically controls said signalingmechanism, and a suitable source of electric energy for said lattercircuit connections.

6. In a. block system for railway bridges, the combination with arailway bridge, of a length of track crossing said bridge, trainactuated contact devices associated with said length of track, signalingmechanism associated with said bridge, circuit connections forcontrolling said signaling mechanism and including said train actuatedcontact devices, mechanism for holding said train actuated contactdevices yieldably in the position in which they were left after thepassage of a train, a magnet controlling said latter mechanism, a secondset of train actuated contact devices andcircuit connections ineludingsaid second set of contact devices and said magnet.

7. In a block system for railway bridges, the combination with a(lrawbridge, of a length of track crossing said bridge, electricalcontact devices actuated by the passage of the train over said length oftrack, power mech anism for operating the bridge, normally closed.circuit connections for controlling said power mechanism and includingsaid trainactuated contact devices, whereby said power mechanism iselectrically controlled by a train entering said length of track.

8. In a block system for railway bridges, the combination with a railwaybridge, of a length of track crossing said bridge, power mechanism foroperating said bridge, train controlled mechanism associated with saidlength of track and controlling said power mechanism.

9. In a block system for railway bridges, the combination with a railwaybridge, of a length of track crossing said bridge, a blocking leverpivotally mounted between its ends in the approach to said bridge andadapted to be oscillated by the traverse thereover of a traversingmember carried by a train, locking mechanism associated with said lever,and means controlled by the bridge operation and in turn controllingsaid locking mechanism.

10. In a block system for railway bridges, the combination with arailway bridge, of a length of track crossing said. bridge, a block inglever pivotally mounted adjacent to said length of track beyond one endof said bridge and adapted to be oscillated by the traverse thereover ofa traversing member carried by a train when said lever is in unlockedcondition, locking mechanism controlling said lever, a magnetcontrolling said locking mechanism, train actuated contact devicescontrolled by the bridge operation and circuit connections includingsaid contact devices and said magnet whereby said blocking lever isplaced in danger position upon the opening of said bridge.

11. In a block system for railway bridges, the combination with arailway bridge, of a length of track crossing said bridge, a blockinglever pivotally mounted between its ends adjacent to said length oftrack beyond the respective ends of said bridge, locking mechanismcontrolling the respective ends of said bridge, locking mechanismcontrolling the respective blocking levers, a magnet associated witheach locking mechanism and controlling the latter, contact devicescontrolled by the operation of said bridge, and

circuit connections including said contact and said magnets whereby saidlocking levers are placed in danger position upon the opening of saidbridge.

12. In a block system for railway bridges, the combination with arailway bridge, of a length of track crossing said bridge, trainblocking mechanism associated with said length of track beyond therespective ends of said bridge, each of said mechanisms comprising ablocking lever, a locking device as sociated with said lever, and amagnet controlling said locking device, contact devices controlled bythe bridge operation, and circuit connections including said contactdevices and said magnets whereby said locking levers are electricallycontrolled by said bridge.

13. In a block system for railway bridges, the combination with arailway bridge, of power mechanism for operating said bridge, trainactuated contact devices associated with said length of track, a magnetcontrolling said power mechanism, and circuit con nections includingsaid magnet and said train actuated contact devices.

14. In a block system for railway bridges, the combination with arailway bridge, of a power mechanism for operating said bridge, a magnetcontrolling said power mechanism, train actuated contact devices beyondthe respective ends of said bridge, circuit connections including saidmagnet and said contact devices whereby a train approaching said bridgeplaces said power mechanism in inoperative condition and then restoresit to normal after it has passed over the bridge.

15. In a railway block system for bridges, the combination with abridge, a length of track crossing said bridge, means for locking saidbridge, normally energized magnets maintaining said locking mechanism inunlocked position, normally closed train-actuated contact devicesassociated with said length of track and adapted to be actuated by apassing train, means for yieldably holding said contact devices in theposition in which they are left by the passage thereover of a train,means for restoring said contact devices to normal, and circuitconnections including said contact devices and magnets.

16. In a block system for railway bridges, the combination with abridge, of a length of track crossing said bridge, a train actuatedlever associated with said length of track, locking mechanism associatedwith said lever, a magnet controlling said locking mechanism, circuitconnections extending across said bridge and including said magnet, afusible link included in that part of the circuit connections whichextend across the bridge, contact devices controlled by said lever,yieldable latch mechanism associated with said lever and adapted tomaintain said contact devices yieldably in open or closed position, amagnet controlling said latching mechanism and circuit connectionsincluding said magnet, and a suitable source of electric energy.

17. In a block system for railway bridges, the combination with a bride, of a length of track crossing said bridge, electrically controlledmeans for locking said bridge, a magnet controlling said locking means,a set of normally closed contact devices, means for maintaining saidcontact devices yieldably in open position, means for automaticallyrestoring said contact devices to normal, circuit connections includingsaid magnet and said set of contact devices, and a train-actuated leverassociated with said length of track and controlling said contactdevices, whereby said locking mechanism is electrically controlled bysaid lever.

18. In a block system for railways, the combination with a bridge, of alength of track crossing said bridge, power mechanism for operating thebridge, a blocking lever associated with said track, bridge controlledmeans in turn controllingsaid blocking lever and means whereby saidblocking lever controls said power mechanism.

19. In a block system for railway bridges, the combination with a lengthof track, of a combined blocking and train actuated bridge controllinglever, a locking mechanism for said lever, said combined lever operatingas a blocking lever by the rigid holding of one end in an elevatedposition by said locking mechanism, and operating as a bridgecontrolling lever by the alternate elevation and depression of one endof said lever by the passage thereover of a traversing member carried bya train, and a bridge controlled by said combined blocking andcontrolling lever.

20. In a block system for railways, the combination with a length oftrack, trainactuated contact devices associated therewith, signalingmechanism associated With said bridge, a local battery circuit foroperating said signaling circuit, contact de vices included in saidlocal battery circuit, a magnet controlling said contact devices, andcircuit connections including said magnet and said train-actuatedcontact devices, whereby the latter electrically controls said signalingmechanism, and a suitable source of electrical energy for said lattercircuit connections.

GEORGE W. NISTLE. BERNARD WV. BRADY. EDWARD INSKIP. Witnesses:

EMILIE ROSE, F. L. BELKNAP.

